Behavioral neurological measurements in the neonatal period can provide insight into the behavioral abilities of newborns, facilitate early development of intelligence, and enable early detection of minor brain injuries for early intervention. Early intervention will greatly promote the plasticity of the injured brain to achieve good functional compensation and prevent disability.
First, the neonatal nervous system characteristics
The neonatal nervous system is anatomically immature, significantly different from that of adults in terms of chemical composition and physiology, and functionally immature, with a significant portion of neurological functions controlled by the brainstem and spinal cord, such as infantile reflexes, such as hugging, holding, stepping, placing, etc., representing the release of primitive nerve cell functions that are not subject to the constraints of the higher brain. Because its hindbrain performs the primary function. Anterior brain damage caused prenatally or perinatally is not significant in the neonatal period and only gradually manifests as the child matures and takes on more complex behaviors. There is a definite influence of the postnatal environment on brain development, i.e., the development of brain function is plastic. The immature brain is the most plastic, so early detection and intervention are emphasized.
Wolf et al. found that newborns from sleep to awakening can be divided into six states of consciousness: deep sleep, light sleep, drowsiness, quiet awakening, active awakening and crying, each of which has some specific behaviors, and found that newborns have certain sensory abilities in vision, hearing, as well as smell, taste and touch, and have the ability to coordinate the movement of hands and feet and the ability to imitate the outside world such as the mother. For example, newborns look at people’s faces in a quiet and awake state, turn their heads toward the sound, mimic tongue extension, and twist their bodies to the rhythm of external speech.
Second, newborn behavior
1, newborns have a lot of surprising abilities, will cry, laugh, eat, can listen, see, smell, have the sense of taste and touch.
(1) vision: 28 weeks of gestational age react to light, 37 weeks with the shimmering eyes, strong light can induce the newborn blink reflex. After birth, the baby can see. A few minutes after birth, they can pay attention to the figure of human face longer than white paper. After birth, they can follow the red ball (8-10cm diameter ball, swinging at 20-25cm in front) to gaze at 90° angle.
(2) Hearing: Within a few days after birth, auditory stimuli are transmitted mainly through the spinal cord tissue. Loud sounds cause blinking, or hugging reflex, and can change from quiet to crying or from crying to quiet. In the awake state, the eyes and head are used to find the sound source. In utero, the fetus can hear various sounds inside the mother’s body, speech and outside music, and still keep the memory after birth.
(3) Smell: The sense of smell develops early, such as looking for breast milk, and can use the nose to identify which breast pad is its mother’s, and turn the head in this direction. They express displeasure at strong odors and do not form a scent-induced food conditioned reflex in the first month after birth.
(4) Taste: A few days after birth, they can suck on sweet tastes, frown on salty, sour and bitter tastes, close their eyes and use their tongues to put bitter objects on top.
(5) touch: after birth, there is the sense of touch, the most sensitive around the mouth and lips, when there is something in contact with the sucking action, objects touching the heart of the hands and feet to produce grip reflex, response to cold and painful stimuli, etc.
(6) Movement: Neonatal movement is mostly unconscious or reflexive, and both limbs show symmetry in range of motion, muscle strength and muscle tone. The flexor muscle tone is greater than the extensor muscle tone, and the upper and lower limbs are in a flexed position when quiet. The thighs are mildly abducted when lying supine, and the knees, hips and ankles are flexed. The head is tilted to the side when lying attached, the hip is flexed, the knee is flexed below the abdomen, and both hands are in a lightly clenched fist, with the thumb placed outside the other four fingers. There may be spontaneous opening and fist clenching movements.
(7) have a certain degree of interaction with the outside world and the ability to recognize the world, imitation movements, such as stretching the tongue and opening the mouth.
2, the newborn already has the ability to form habits, the newborn is in a habit-forming state is their defense response to excessive environmental stimuli.
The newborn’s movements are governed by the newborn’s intracranial “biological clock”. This movement can be traced back to the fetus, and has been indicated by ultrasound observations that the fetus at 16-20 weeks has spontaneous rhythmic movements of the arms, legs and trunk. After birth, the fetus will raise its shoulders, arms, eat fists, see, laugh, yawn, open its mouth, stretch its tongue, etc.
C. Normal neonatal wake-sleep cycle
There is a certain regularity in the changes of this cycle, including six states. The normal cycle is about 45-50 minutes.
1.Deep sleep: eyes closed, no eye movement and natural body movement, regular breathing.
2, shallow sleep: eyes closed, rapid eye movement under the closed eyelids, reduced natural trunk movement, irregular breathing.
3.Drowsy: eyes can be opened or closed, eyelids flicker, and there are different degrees of trunk movements.
4.Quiet awakening: eyes open, little activity, can focus on the stimulus source.
5.Activity arousal: eyes open, more activity, not easy to focus on.
6.Crying: not easily responsive to perceptual stimuli.
Neonatal neurobehavioral measurements are required to go through the above states, while neonates with central nervous system damage lack the expected cyclic changes.
Fourth, the significance of neonatal behavioral neurological measurement
1. NBNA can be used as a normal value for neurological assessment of behavior in normal newborns. This measurement method is stable, reliable, economical testing tool, simple and easy to master, practical, time saving (10 minutes), and repeat examination is not harmful to the child. Regional differences have no significant effect on the scoring results.
2. Behavioral assessment of newborns is beneficial to optimal parenting and early intellectual development. With both parents present during the examination, they can understand the ability of the newborn’s behavioral reflexes, enhance the confidence of both parents, and contact with the newborn to strengthen the training and promote the development of intelligence and physical strength.
3, Early detection of neonatal behavioral neurological abnormalities caused by brain injury, making full use of the early neurological plasticity timing for early intervention, improving the environment, and training to promote compensatory neurological recovery.
4.It can be used as a means to detect the impact of perinatal high-risk factors on the newborn. For example, NBNA is currently used in China to dynamically observe the effects of neonatal asphyxia, hypoxic-ischemic encephalopathy and small-like infants on neonatal behavioral neurology, which has a more obvious correlation with prognosis.